As the quantity of data stored in digital form continues to rapidly increase, maintaining secure control of sensitive individual, business, financial institution, and government agency digital data becomes increasingly difficult. Data is often stored, for example, as discrete magnetization patterns on magnetic data storage media, such as magnetic tape or disks. One aspect of digital data security for magnetic media is erasure, i.e., degaussing, of the media. Degaussing is commonly performed to eliminate stored information from magnetic media, and can be very important, particularly when the data to be erased is confidential, private, or highly classified. Degaussing is also commonly performed during media fabrication, e.g., prior to servo writing to ensure that the servo patterns can be properly written.
In general, degaussing of a magnetic medium involves exposing the medium to a magnetic field of sufficient strength, e.g., flux density, to randomly magnetize the medium, thereby destroying the discrete magnetization patterns which comprise the stored data. Degaussing devices may employ a variety of techniques to create such a magnetic field, such as use of alternating or pulsed current to drive a coil. These techniques provide an alternating or pulsed magnetic field, respectively. Other degaussing devices employ a fixed magnet. Fixed magnet degaussing devices are typically used for “emergency” data destruction applications where a means to destroy data without external power is required.